Construction / Adhesives & Sealants / Cristobalite


Mineral: Cristobalite


Cristobalite can be characterised by:

  • High brightness
  • Relatively high Mohs hardness of 6.5
  • Relatively low refractive index, making it a transparent filler in various binders
  • High inertness in various media
  • Transparency for UV-radiation (i.e. suitable for UV-curing processes)

Note when using cristobalite: depending on the particle size distribution of the product, it can be labelled (STOT RE 2 or STOT RE 1). For more detailed information, visit


Basic properties

Property Value Unit
Moisture [%]
pH 9 [-]
Hardness (Mohs) 6.5 [-]
Refractive index 1.48 [-]
Colour (D65/ 10°) L* 98 [-]
Density 2.3 [kg/ dm3]



Name Grade D50 D90 OA
Sibelite M3000 17 40 26
M3500 10 30 26
M4000 6 12 27
M6000 4 8 28


Production Location: Dessel (BE), Maastricht (NL)


Cristobalite will provide:

  • Dirt pick-up resistance: the presence of cristobalite improves the sealant’s resistance to dirt (from the atmosphere, for example)
  • UV resistance and weatherability: due to its inertness, cristobalite supports good UV and weatherability performance to sealants and adhesives when applied outside





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